This invention relates to a self-contained apparatus and an associated method for determining and displaying the cost of a telephone call and/or related parameters.
Telephones containing memory arrangements from which the cost of a telephone call can be determined while the call is in progress without receipt of any call cost information from the telephone central office through which the call is placed have been known for several years. See, e.g., U.S. Pat. No. 4,122,308 to Gerald J. Weinberger and Stanley F. Miller entitled Telephone Call Meter. For a somewhat different arrangement for providing telephone call cost information, see U.S. Pat. No. 4,091,238 to Samuels et al.
Calculator-type devices are known that display information as to the cost of a call on a real time basis, but are not self-contained. That is, the user is required to input call cost parameters such as initial period duration, next period duration, initial period cost and next period cost and to press a start button when the call is initiated, after which the device displays the cost of the call while the call is in progress.
Private pay telephones having self-contained telephone rate memory arrangements are now in common use, and are capable of displaying call cost information before the call is placed and while the call is in progress. Such telephones, however, are relatively expensive and are not capable of displaying the total cost of a call in response to information keyed in by the user as to the number being called and the duration of the call, without actually placing the call. Nor do such telephones provide information to the user as to the particular exchange being called, rate variations with time of day or day of week, or rates of various long distance carriers.
There is a need for a relatively inexpensive self-contained device for displaying the aforementioned types of information. Such a device would be useful for verifying the accuracy of the charges on telephone bills, for determining the location of a number to be called, for facilitating the choice of a long distance carrier based on the exchanges most frequently called by the user, and for related purposes.
Accordingly, an object of the present invention is to provide an apparatus and method for providing such information which is easy to use and which is capable of being manufactured at a relatively low cost.